Mizue Tani is a Japanese author known primarily as the creator of the light novel and manga series The Earl and the Fairy. Born on February 3 in Mie Prefecture, she is a graduate of Mie University. Her career began in 1997 when she won an honorable mention in the sixth Shueisha Roman Grand Prize for her work Paradise Renaissance.

Tani is most recognized as the original creator of The Earl and the Fairy, a fantasy romance series that began as a collection of light novels published by Shueisha under its Cobalt imprint. The series, illustrated by Asako Takaboshi, ran for thirty-three volumes from March 2004 to December 2013. The story is set in Victorian Britain and follows Lydia Carlton, a young woman who can see fairies, and her adventures with Edgar Ashenbert, a man claiming to be the Blue Knight Earl. The success of the light novels led to a manga adaptation illustrated by Ayuko, which was serialized in the shōjo magazine Margaret from August 2008 to April 2010 and compiled into four volumes. A twelve-episode anime television series adaptation produced by Artland aired from September to December 2008, and a visual novel for the PlayStation 2 was released in April 2009.

Beyond The Earl and the Fairy, Tani has authored several other book series. Her notable works include the fourteen-volume series The Witch’s Marriage, the five-volume series The Little Lady of the Flowering Hill, and the three-volume Skyscraper Doll series. She also created the series Ijinkan Garou and Omoide no Toki Shuurishimasu, with the latter being noted as a hit in Japan that sold over two hundred thousand copies. Her body of work consists primarily of light novel series and standalone volumes published by Shueisha, establishing her as a significant contributor to the fantasy and romance genres within Japanese publishing.